Grate bar



March 17, 1931. Q HAGEDQRN T' 1,796,868

GRATE BAR Filed Jan. 3. 1929 (MRI. HAG'EDOR/V dOlf/V MHAGEDOR/V WWMMFatented Mar. 17, 1931 umren STATES PATENT OFFICE GR-ATE BAR.

Application filed January 3, 1929.

Our present invention relates to improvements in grate bars for use infurnaces of various types, and involving the use of interchangeable,renewable, fuel plates with the supporting parts of the bars. Theprimary obJect of the invention is to render more durable the grate barsand extend their pe riod of use by providing venting for the circulationof air currents through the 'different parts of the grate bars so thatthe heat may uniformly be distributed to insure uniform expansion andcontract-ion and thus avoid warping or burning of the bars. Means arealso provided for relieving the grate bars of excess heat, by thecirculation of water through the bars, thus conveying excess heat fromthe bars and cooling them to such an extent as to prevent warping andburning under excessive heat in the furnace. The invention consists incertain novel combinations and arrangements of parts as will hereinafterbe more fully set forth and claimed. In the accompanying drawings wehave shown one complete example, and a :4 slight modification thereof,of the physical embodiment of our invention, wherein the parts arecombined and arranged according to modes we have thus far devised forthe practical application of the principles of our invention, and thegrate bars exemplified have successfully and extensively been used, andare now being used in actual practice.

Figure 1 is a view in side elevation of one of the grate bars supportedbetween furnace walls and equipped with the water cooling pipes. Figure2 is a. perspective view of one of the bars with the fuel platesremoved, and broken away for convenience of illustration.

Figure 3 is a longitudinal sectional view of a grate bar and its fuelplates, as at line 3-3 of Figure 2.

Figure 4-.is a perspective View of one of the fuel plates, inverted,used in Figures 1 and 3. Figure 5 is a transverse vertical sectionalview at line 55 of Figure 1. Figure 6 is a perspective View of amodified form of fuel plate, inverted, and Figure 7 is a sectional view,similar to Figure 5, but with the water pipes omitted and a modifiedform of fuel plate illustrated, as shown in Figure 6.

Serial No. 330,993,

In the preferred form of the invention we have shown in Figure l a usualfront Wall I, and rear wall or arch 2, of a furnace, the wall ora-rch-2being cut away in its front face at 3 to allow for expansion of thegrate bars under heat in the furnace. At the front of the furnace asupporting ledge 4L or other suitable support is provided, and acomplemen-tary support 5 is used on the front of the arch'or rearwall,between which supports the grate bars are supported to; permitlongitudinal expansion and contraction.

Each grate bar includes-the hollow member having spaced side. walls 6and: 7 that are, joined by the integral intermediate webs 8', and theend bars 9, the latter having lateral lugs 10 to space adjoiningbars'for the formationof vertical slots between the bars to perunitventing of air currents through the grate. p

' Inthet'op edge of'eachof the-side walls ofthe grate we fashion alongitudinally extending groove 11,, that is, semi-circular in crosssection, and ext-endsfrom endtoe-nd? ofthe gratebar, for the receptionof water pipes 12 that lie in the grooves; Fhese pipes are connected attheir opposite ends to headers or manifolds 13 and Matthe remote facesof'thefront and rear walls of the furnace, and the pipes andheaders formacirculation system for- Water throughout the whole grate for coolingthe latter-or for relieving excessiveheat in the bars. The waterissupplied to the system through iinlet -pi5pe15 at one endand an out.-let pipe-1T is shown at the other end of the system, a control valve 16being used in the V inlet pipe for control of the water flowing throughthe coolingcoils of the grate.

In combinationwith the grate bar we use removable, interchangeable, andrenewable fuel plates 18, three of which are shown in- Figure 1, but of"course; more plates are used: on alongergrate bar. These platesare'concave-convex'or arched with roundedtops, and are provided withholes 19 for venting, and at thei nundersides each plate isprovided withlongitudinally extending grooves. 20,. semi; circular. in cross sectionand; complementary tathe grooves; in the: top, edges ot the; walls ofthe; ban, Between. the grooved: edges of the bar and the grooved edgesof the plates the water pipes are enclosed and the pipes provideretaining means for the plates to hold them against lateraldisplacement. The fuel plates also have side lugs 21 at their oppositeends, complementary to the lugs 10 at the sides of the ends of the bars,and designed to provide for venting slots in the grate between adjoininggrate bars.

On the under face of each fuel plate are a pair of integral lugs 22 and23 extending transversely of the plate, one lug as 22, being locatedadjacent an end of the plate while the other lug is located a greaterdistance from the opposite end of the plate. The length of these bottomlugs is such as to have the lugs fit in between the spaced walls 6 and 7of the grate and allow for expansion.

In actual practice and extended use of the grate bars with the coolingsystem of water circulation through the pipes we find that the gratebars are more durable and that they have a greater resistance againstwarping, burning, or deformation of the fuel plates due to the heat ofthe furnace. The water pipes are so situated as not to interfere withventilation through the grate and their enclosure between the grate barsand the fuel plates protects and shields them from direct contact withflames, or with ashes and fuel.

I Vhen the presence of the cooling water pipes is not necessary, thefuel plates 18 may be replaced by interchangeable plates 24 from whichthe semi-circular grooves are omitted, but which are fashioned at theirunder edges with transversely extending bosses 25 which rest upon thegrooved edges at the tops of the sidewalls 6 and 7 of the grate barwalls, as indicated in Figures 6 and 7 wherethis modified form of thefuel plates is shown. v

It will be noted that the transverse lugs 22 are nearer an end of thefuel plate than the lugs 23, and this arrangement of lugs in the seriesof plates, as in Figures 1 and 3, allows for longitudinal expansion ofthe plates in the same direction, that is, to the right as in Figure 1.The location of the lugs at difierent distances from their adjoiningedges or ends also prevents likelihood of the'plate expanding to such anextent as to wedge the lugs between adjoining intermediate webs orbetween intermediate webs and adjoining end webs. The fuel plates whenworn may thus readily be removed and replaced by fresh ones, thetransverse lugs at the under side of the plates being arranged in thesame relative positions in each fuel plate. 7 p

Having thus fully described our invention, what we claim as new anddesire to secure by Letters Patent is In a grate bar the combinationwith spaced side walls having end bars and intermediate tures.

" CARL HAGEDORN.

JOHN IV. HAGEDORN.

